Method of separating dispersed matter from fluid masses



y 1953 R. D. SIMPSON ETAL 2,638,218

METHOD OF SEPARATING DISPERSED MATTER FROM FLUID MASSES Filed Nov. 21,1949 INVENTORS 205E127 D SIMPSON ELW/N M GORDON By Fem/K 61420024 JOHNHg/TCOB 2% Patented May 12,195?) umren STATES PATENT OFFICE METHOD OFSEPARATING DISPERSED MATTER FROM FLUID MAS SES Robert D. Sifiipsdn andElwin V. Gordon, San Leandro, Frank cardoz naywam, and John H. Jacobs,Oakland, Calif.', assignrs to Farm Production Engineers, 1 11a, Oakland,Calif., a corpcration of California Application November 21, 1949,Serial No. 128,586

Gla'iins. 1

This invention relates to the separation of pi'ecipitable substancesfrom a fluid carrier. 7

An object of theinvention is to provide a method for effecting the rapidand continuous halidling of unusually large volumes of mixtures fidiiiwhich it is desired to separate selected components of specific unitmass weight.

Another object of the invention is to provide a method, for effectingseparation as above set forth, wherein rnihute discrimination may bereadily secured between components of a mixtiiife which Very nearly havethe same it mass weight so that the resultin extraction will possess theleast possible degree of adulteration.

A further object of the invention is to provide a r'iiet'hod wherein bythe application of opposmg forces to a mass of ih'ixed material adelicate degree of unbalance may be established in the mass by means ofwhich a selected component of the mixture may be caused to pass more orless rapidly from the mass.-

Still another Object of the invention is 110' provide a method ofseparation as above described which will function equally as efficientlywith aqueous i'nixltures as with masses in which a gaseous inediurhcomprises the suspending or carrier vehicle.

The ihventi'on possesses other objects andfeatures of advantage which,together with the .fQlE- going, will be spe'ifically'set forth 'iritlierenew; ing detailed. description of the invention. It will be understoodthat the invention is not to be limited to exemplary apparatus or thespecific view taken in the plane indicated by the line 4-4 of Figure 3.

Figure 5 is a horizontal sectional view, taken substantially in theplane 05: the line 3- 3 of Figure 1 and illustrating diagrammatically aportion of the forces imposed on the .inaterlial par ticles in theseparator.

Figure 6 is a vertical sectional view substanz tiall'y equivalent to thelower portion of- Figure 1 and illustrating diagrammatically otherfdrce's imposed on the particles within the separator Figure"? is avector diagram of the direct and resultant force's imposed on particlesduring their separation.

In broadest terms, our invention comprises releasing masses of mixedfluid and dispersed matter to fall by gravity along a defined path,applying to the masses force to effect deflection ofa selected componentof the dispersed niatt'er siihstantially laterally of the path,arresting the deflection movement of the selectedcomponent at an outerzone of the path, permitting continuing movement of the selectedcomponent along thepath in the aforementioned outer zone thereoi',imposingon the remaining components of dispersed matter excepting theselected one thereof a force arresting movement along the path of thesaid remaining components, collecting the selected com'pone'nts at anintermediate point in the path and subsequently directing the remainingcomponents and fluid along the path away from the collected selectedcomponents.

There are numerous ways in which the exact above procedure or :afunctional equivalent thereof ma lie carried out but we have chosen forpurposes er illustration the particular mechaiiism or the drawing whicha preferably axially vertical housing 2 is provided having therein apreferably cylindrical and downwardly convergent separation chamber 3communicating through a' duct 4 with a secondary chamber 6 of verticallyflattened globular form containe d in a housing f corresponding shapedisposed aidal- 1y below the housing 2 and provided in the bottomsurface thereof with a discharge spoilt 1 capable .oihein-g opened andclosed by a suitable control valve 8. Reference is also made herein tothe apparatus disclosed in our copending application, SerialNo. 149,346.

h Means tor delivering material to be separated into the separationchamber 3 is here shown as comprising an inlet vconduit 9 which isarranged to discharge tangentially into the upper portion of theaforesaid chamber and which is connected through a pump l l, orothersuitable flow ind-11cing means, with a supply duct it into which fluidand entrained material may be introduced, preferably by suction existingin the said duct, from a material-supply hopper 113 or vother equivalentmeans. Where the en-trained material zoomprises comminutecl solid mattercarried in a fluid carrier, whether air or liquid, the end of the supplyduct 32 may be equipped with a suction nozzle [4 immersed in the mass ofmaterial I6 contained in the hopper [3; the pump H under suchcircumstances serving to lift the material 18 from the hopper, togetherwith the carrier stream which may be ambient air about the hopper orliquid introduced into the latter in the required suitable amounts, andto forcibly discharge the mixture of carrier vehicle and entrainedmaterial into the separation chamber 3. In some instances, such as whereseparation of seed values from grain is desired, the pump ll maycomprise a fan-type blower into which cut stalks with their attachedseed heads may be fed through the suction duct l2, the blower thereuponthreshing the grain and effecting thorough detachment of the seeds orkernels from the heads, the resulting mixture being then conveyed by thecarrier air stream into the separation chamber 3.

As the carrier stream of fluid tangentially enters the upper portion ofthe separation chamber 3 the mass of fluid and entrained material willbe caused to whirl rapidly about the vertical axis of the chamber withthe result that both centrifugal and gravitational forces acting on theheavier components of the mass will primarily cause the components towork their way radially outwardly of the mass to occupy a peripheralzone thereof limited in radial dimensional extent by the inner wallsurface of the chamber and secondarily will cause the concentratedheavier components to gradually move, under the influence of gravity,downwardly along the converging wall surfaces toward the throat 4. Inthe case of threshed grain or the like, the weightier seeds or kernels.will act similarly to the heavier components of the aforesaid mixture,the lighter tares forming a whirling central core mass in the separationchamber which will also move under the influence of gravity downwardlytoward the throat 4.

In the throat 4 and separating the chamber 3 from the space therebelow,here shown as the chamber 6, is disposed what may be termed a gridcomprising a plurality of circumferentially spaced vanes I I radiatingfrom a common center which coincides with the central axis of thechamber 3 and arranged so that their facial surfaces angularly intersectthe said axis of the chamber 3 and arranged so that their facialsurfaces angularly intersect the said axis, the degree of saidangularity being dependent upon several factors and the nature of themixture in which particle separation is to be effected. Each vane I! incross-sectional form is preferably curvate rather than fiat, thesubjacent surface facing the chamber 6 being concave so that any fluidstream which may move from the chamber 6 upwardly into the chamber 3 isintercepted by the vanes and caused to enter the latter chamber intangential relation to the vertical axis thereof and in a degree ofangularity, normal to the axis, which is a function of the verticalinclination of the vanes. The preferred arrangement of the parts is suchthat the aforesaid entering stream will be caused to conform indirection of rotation with the whirling mass of fluid in the separationchamber and will smoothly merge therewith so that minimized turbulencein the plane of confluence of the fluid masses will obtain.

Means is provided in the separation chamber 3 for effecting continuousremoval of core portions of the mass of carrier fluid and entrainedsubstances other than the concentrations of selected particles in theperipheral zone of the mass and for allowing the said concentrations tosettle downwardly toward the upper plane of the grid preparatory tofinal and complete separation from the parent mixture. Arrangedconcentrically of the separation chamber and extending verticallydownwardly therein is an exhaust duct l8 having at its lower end anaxially and vertically adjustable tubular section 19 provided at itslower end with a downwardly flared collector bell 2| capable of beingpositioned variably above the upper horizontal plane of the grid. Theopposite end of the exhaust duct is is connected to suitable flowinducing means here shown as the suction inlet of a blower or similarrotary pump 22 whose discharge 23 may be directed into the atmosphere orinto a suitable distribution duct for disposal. In the separation ofgrain, for instance, from its supporting stalks and seed heads, the massof previously threshed and relatively detached seeds and tares or theintegral grain immediately after harvesting, is brought into proximitywith the suction nozzle i4 and is drawn, by suction existing in the duct[2, into the pump or blower I I wherein the mixture of grain and carrierfluid is vigorously and thoroughly agitated so as to effect the mostcomplete detachment of the seeds or values from the tares, the resultingmixture being then discharged as previously described tangentially intothe separation chamber 3 through the lead-in conduit 9. Once in theseparation chamber, the solid particles'and tares will be whirled,together with their mass of carrier fluid, about the vertical axis ofthe chamber with the result that the heavier particles will be urged, bycentrifugal force, radially outwardly of the mass to occupy theperipheral zone of the latter while the core mass will comprise thelighter tares and other undesired components of the mixture. Theadditional force of gravity will be exerted on both the selected heavierparticles and the core mass, the former being the most affected, so thatboth components will move downwardly toward the grid at the bottom ofthe separation chamber while still whirling within the chamber.

The suction pump or blower 22, being activated, establishes a suctioncurrent in the exhaust duct [8 and in the bell 2|. In the case of thestructure-of Figure 1 wherein the space below the grid is open to theatmosphere, the suction flow moving in the duct 18 will induce an upwardflow of atmospheric air through the grid and past the vanes thereof withthe result that the induced stream in emerging from the grid at theupper plane surface thereof is, as previously explained, whirling insubstantial conformity with the rotational movement of the mass ofmixture in the superposed separation chamber 3, As the entrainedmaterials in the fluid mass contained in the separation chamber descend,the radially inner core portions of the mass, comprising fluid and therejected particle components of the mixture, upon coming intosubstantial registry with the bottom plane of the bell will be broughtunder the influence of the suction flow entering the bell with theresult that all components other than the particles occupying theperipheral zone of the mass will be drawn out of the separation chamberand disposed of as previously mentioned.

A peculiar action takes place during movement of selected materialparticles toward and through the grid unit. As hereinbefore specified, aconstantly moving stream of fluid is flowing at prescribed velocityupwardly through the grid unit between the vanes H as shown Figure A.Each division of the stream passing upwardly between acent vanes isadjusted to move at such critical velocity that all components of themixture of fluid and entrained particles immediately above the gridinsthe separation chamber, the exception of the selected particleswhichware to he recovered, are buoyed upwardly and sustained insuspension above the grid where they will ere-m tually come under theinfluence of the suction draft flowing in the duct -13 and will becarried on and disposed of. Where air comprises the stream movingupwardly th ugh the grid, it has been fnund'th-at each :di sion of thestream the latter varies in clensity and velocity in successive radialincrements of cross-sectional area from a maximum at the "center of thestream division to a lesser amount the zonal extremity thereofimmediately adjacent the surfaces of the vanes.

This means that at circumferentiaily spaced points around the upperfacial area of the grid uni-t, fluid jets will be projected generallyupwardly at their centers possess suiii-cient velocity only slightlyless than that required to impart run "buoyancy to the selectedparticles to "be recovered and more than sufficient to double backagainst the force of gravity all other components of the fluid bornematerial. "I he spaces between the higher'velocity centers of adjacentlots will be traversed by outer longitudinal zones of the jets havinglesser "velocities which, however, are not so low as to allowsubstantial amounts of the rejected components of the fluidbornematerials to gravitate toward and to penetra-te the grid unit. It willbe seen that as the concentrate of selected particles moving downwardlyalong the inclined sidewall surfaces of the separation chamber '3 reachthe upper plane of the grid unit, they will be caught in the zone ofsubstantial equilibrium between the upper swirling'fiuid mass theseparationchamber and the similarly swirling flow of fluid risingthrough the .grid unit. This will cause the particles to become spreadout laterally in a horizontal plane slightly above the upper facialplane of the grid unit and to be carried along the former plane for oneor more revolutions of the fluid mass during which time gravitywillactupon the particles and cause them to approach and skim over the'said facial plane of the grid as indicated in Figure 4.

As the "latter particles lose their momentum, they will pass over theupper ends of the vanes l1 and vertically downwardly into the streamdivisions moving upwardly between the vanes, each particle penetrating astream until the former reaches a velocity zone of the stream which willresist its-fall whereupon thepartic'le will rebound into or through oneor more of the adjacent zones of lesser velocity thereafter againfalling substantially vertically until the aforementioned highervelocity zone is reached, resulting in the above described cyclerepeating itself, Thus, as indicatedin Figure 4, the particleswillcascade downwardly along the stream divisions, and counter to movementof the latter, into the comparatively .low velocity fluid mass existingbelow the grid unit whereupon the particles may fall unimpeded throughthe discharge spout 2'4 and into any suitable receiver placed below thespout.

The forces exerted on each particle from the time that it enters untilthe time that it leaves the separation chamber are rather complex andare believed to be adequately illustrated in Fignres 5,, .6 and .'l ofthe drawing. Here, it willlbe seen, the arrows C and G representrespectively the horizontally outwardcentrirugal iorce exerted on theparticles by the whirling motion of fluid carrier and entrained materialwitlun the separation chamber and the perpendicular force constantlyexerted on the particles by gravity. .Also present and represented bythe arrow T is the tangential force substantially horizontally at rightangles to the centrifu al force line C which indicates the 'impellingforce behind the particle causing the latter to whirl with the parentmass :in the separation chamber. Directly opposing the centrifugal andgravitational ionces (3 and is the suction fouce S created :by theexhausting fluid flow in the duct :ll! which, :as shown Figured, isdirectly opposite :to the centrifugal force at the plane of the lowerend of the suction bell :2l and which is more vertically angularlyrelated to the centrifugal force at the upper facial plane of the gridunit.

the two force arrows S shown in Figure '7 represent the space betweenthe relatively confronting plane faces of the suction hell 2;! and gridurn-t in which radial opposition to the centrifugal force takes place.The upward ccomponent of the suction force 8 induces the upward :flow offluid through the grid unit, and creates the buoyancy force B which is.in direct opposition to the force G of gravity. All of these forcescombine to produce a resultant R which represents both the driving forcecausing :the particle to substantially float above the grid unit beforesettling thereon andpassing therethrough. In normal operation, theupdraft or buoyancy iiorce 3 :must he maintained slightly less than thegravitational force so as to produce aresultarrt R0 not exceeding thesuction fame S, otherwise the particles which are to be separated fromthe fluid imass will be caught up by the suction draft in the duct IBand discharged with the tai lings from the separation chamber. it willbe seen therefore that it is possible, by regulating the updraft .orbuoyancy force B, so that it is exceeded only very slightly by thecountering or gravitational force G, to effect efiieient separation ofparticles from a mixture which .dif r fers in unit mass weight to a verysmall degree in relation .to the similar characteristics of otherparticles which are 1103138 rejected.

In the separation of .certain substances such as minerals fromcomminuted ore masses it is preferred that liquid be substituted for airas the carrier vehicle, in which :case the slightly modified form ofapparatus, shown :in Figure :2, is required to effect selection ofdesired pompo- 'nents of a mixture in accordance with the method of ourinvention. As here shown, the secondary chamber 6 is provided with .asupply 'duct 26 for liquid entering the chamber tangentially thereof andpreferably connected, through a control valve 27 or similar element,with a scoop'28 positioned within the separation chamber 3 and facingcircumierentially thereof so as to intercept a portion of the fluid mass2001 1- tained in and revolving about the axis of the latter chamber.The grid unit is also modified to the extent that it is provided with acentrally disposed axially vertical jet tube 28 terminat- 'ing at itsupper end within the bell end '2! of the suction duct 1% and having atits lower end a downwardly flared bell spout '31 positioned within theduct i and sized to provide an annular opening "32 between the peripherythereof and the confronting inner wall surface of "the duct 4. A furthermodification comprises providing a liquid supply duct 33, suitably conetrolled by a valve 34, through which regulated amounts of water or otherdesired liquid may be admitted to the hopper It for admixture with thecontents l6 of the hopper and to provide the carrier vehicle forconveying the said contents into and through the separator apparatus. Inoperational characteristics the modified form of apparatus issubstantially similar to that previously described. When the mixture offluid and material particles entrained therewith is admittedtangentially into the chamber -3 through the discharge orifice of thesupply duct 9, the mass will whirl as before with the heavier particlesto be separated working their way radially outwardly of the mass andconcentrating in a surface layer over the vertical side wall surface ofthe separation chamber, the said concentration then Working its way,under the influence of gravity, downwardly along the said side wallsurface toward the grid unit. Some of the core mass of liquid andparticles of lesser unit mass weight will be drawn into the bell spout2| and out through the suction duct i8, the rate of such removal andconsequently the degree of suction in the latter duct being of coursecapable of regulation by variations in the operating speed of the pump22. Other quantities of the core portion of the fluid mass will beintercepted in its rotational movement by the scoop 28 which will directthe collected fluid through the duct 25 and tangentially into thesecondary chamber 6 wherein the fluid will be caused to whirl inreversed direction to rotation of the fluid mass in the upper separationchamber 3. The admittance of fluid into the second- I grid unit tosupply the buoyant force which is v the full equivalent of the updraftpreviously described, and secondarily a flow into the bell member 3| tocreate a forcible jet of fluid which discharges from the upper end ofthe tube 29 into the lower end of the suction duct I8. This results inthe production of an injector action in the suction tube assisting theevacuation effort of the pump 22 and eifecting more efficient removal offluid and rejected components of the mixture from the separationchamber. The selected components of the mixture which succeed in passingdownwardly through the grid unit, in the manner previously described,cling to the inner wall surface of the chamber 6 due to the action ofthe centrifugal force of the swirling fluid mass in the latter chamberand eventually gravitate downwardly to collect in the spout I fromwhence they may be removed as desired by opening the control valve 8. Itfrequently occurs that in the concentration of selected particles movingdownwardly through the grid unit and passage 4, some particles of mattermay become entrapped which should have been separated from the selectparticles in the chamber 3. In the construction shown, the concentratein passing downwardly through the gap 32 will become agitated to theextent of releasing the undesired particles which will then either becarried upwardly with the fluid flow through the grid unit or will passinto the bell member 3i and be ejected by the jet flow issuing from theupper end of the injector tube 29.

The foregoing description has dealt with the separation from afluid-borne mixture of substance particles, of the components having theheavier unit mass weight. This was done simply to avoid complications inthe description of the procedure rather than to limit the scope of theinvention since it will be seen that the method may be employed toselect from any mixture a particular component having a unit mass weightof intermediate quantity. Such selection may be carried out by running abatch through the processing apparatus so that division of the batch iseffected at the point where the particles of the desired and selectedunit mass weight form either the lightest component of one batch sectionor the heaviest component of the other. The batch section containing thedesired particles is then re-run through the apparatus so as to discardall but the wanted elements. It will be seen therefore that undercertain conditions, discharge of selected components of a mixture may behad at either the normal delivery points below the separation chambersor at the discharge orifice of the exhaust pump or blower 22.

In the above description it will be noted that the flow of fluidentering the secondary chamber 6 is directed in such manner thatrotation of the fluid mass in the latter chamber is counter to that ofthe fluid mass in the separation chamber 3. It would ordinarily beexpected that the rotational directions of both masses should be thesame in order that the fluid rising from the lower chamber 6 through thegrid unit into the upper chamber 2 will flow smoothly between the vanesl1 and be ejected angularly into the upper fluid mass without causingundue turbulence therein. It has been found, however, that for someunexplainable reason, the fluid rising into the chamber of the duct 4from the chamber 6 will reverse its rotational direction of movementwhich, if the mass of fluid in the lower chamber was rotating inconformity with the rotational motion of the separating chamber fluidmass, would cause the rising fluid to strike the vanes ll substantiallynormally to their flow-directing surfaces and create severe tur bulencein the streams emerging from the grid unit into the separation chamber.This condition of course does not obtain in the structure of Figure 1wherein the fluid may freely flow into the bottom of the grid unit.

We claim:

1. The method of separating components of prescribed unit mass weightfrom a mixture entrained in a volume of carrier fluid and includingother components of differing unit mass weight, which comprises movingalong a path a mass including a carrier stream of fluid having entrainedtherein particles of different unit mass weight, whirling said fluid andentrained particles to set up centrifugal force in the mass sufficientto cause segregation of particles of greater unit mass weight fromparticles of lesser unit mass weight in diiferent zones of the mass,subjecting said mass to gravitational force to effect descension of allparticles, inducing a flow of fluid into said mass in opposition to saidgravitational force at suilicient velocity to at least suspend particlesof lesser unit mass weight in said mass and to permit descension ofparticles of greater unit mass weight in said mass, imparting to saidflow of fluid a tangential force so as to cause the latter to move in apath substantially in conformity to the movement of said mass, andcausing said descending mass to be spread out in a generally horizontalplane at the confluence of said flow of fluid and said mass.

2. The method of separating components of prescribed unit mass Weightfrom a mixture entrained in a volume of carrier fluid and includingother components of differing unit mass weight, which comprises movingalong a path a mass including a carrier stream of fluid having entrainedtherein particles of different unit mass weight, whirling said fluid andentrained particles to set up centrifugal force in the mass suiflcientto cause segregation of particles of greater unit mass weight fromparticles of lesser unit mass weight in different zones of the mass,subjecting said mass to gravitational force to effect descension of allparticles, introducing into said mass in opposition to saidgravitational force a flow of fluid at suflicient velocity to at leastsuspend particles of lesser unit mass weight in said mass and to permitdescension of particles of greater unit mass weight in said mass,subjecting said mass to a force to effect a spreading out ofthe mass ina substantially horizontal plane so as to permit said lesser unit weightmass particles to overcome the gravitational force while permitting saidgreater unit weight mass particles to be subjected to said gravitationalforce, and whirling said introduced flow of fluid in conformity with thewhirling movement of said mass to minimize turbulence at the confluenceof said flow of fluid and said mass.

3. The method of separating components of prescribed unit mass weightfrom a mixture entrained in a volume of carrier fluid and includingother components of differing unit mass weight, which comprises movingalong a path a mass including a carrier stream of fluid having entrainedtherein particles of different unit mass weight, whirling said fluid andentrained particles to set up centrifugal force in the mass suflicientto cause segregation of particles of greater unit mass weight fromparticles of lesser unit mass weight in different zones of the mass,subjecting said mass to gravitational force to effect descension of allparticles, directing a portion of said carrier fluid into said mass in aflow in opposition to gravitational force acting on said mass and withsuflicient velocity to at least suspend particles of lesser unit massweight in said mass and to permit descension of particles of greaterunit mass weight in said mass, causing said mass to spread out laterallyin a generally horizontal plane immediately above the confluence of saidflow of fluid and said mass, and whirling said introduced flow of fluidin conformity with the whirling movement of said mass to minimizeturbulence at the confluence of said flow of fluid and said mass.

4. The method of separating components of prescribed unit mass weightfrom a mixture entrained in a volume of carrier fluid and includingother components of diflering unit mass weight,

which comprises moving along a path a mass including a carrier stream offluid having entrained therein particles of difierent unit mass weight,whirling said fluid and entrained particles about a vertical axis to setup centrifugal force in the mass, moving said mass axially to effectvertical and inward movement or all particles, spreading said mass in agenerally horizontal plane, inducing a flow of fluid into said masthrough said spread layer at sufiicient velocity to at least suspendparticles of lesser unit mass weight in said mass and to permitcontinual movement of particles of greater unit mass weight in saidmass, and moving the lighter particles centrally and in a generallyvertical direction.

5. The method of separating components of prescribed unit mass weightfrom a mixture entrained in a volume of carrier fluid and includingother components of differing unit mass weight, which comprises movingalong a path a mass including a carrier stream of fluid having entrainedtherein particles of diflerent unit mass weight, whirling said fluid andentrained particles about an axis to set up centrifugal force in themass, moving said mass axially to effect axial movement of allparticles, spreading said mass in a general transverse plane at saidaxis, inducing a flow of fluid into said mass through said spread layerat sufficient velocity to at least suspend particles of lesser unit massweight in said mass and to permit continual movement of particles ofgreater unit mass weight in said mass, and moving the lighter particlescentrally and in a general axial direction.

ROBERT D. SIMPSON. ELWIN V. GORDON. FRANK CARDOZA. JOHN H. JACOBS.

References Cited in the flle of this patent UNITED STATES PATENTS NumberName Date 1,149,463 Pardee 1 Aug. 10, 1915 1,355,270 Roberts Oct. 12,1920 1,367,635 Sturtevant Feb. 8, 1921 1,660,683 Stebbins Feb. 28, 19281,897,144 Prouty Feb. 14, 1933 2,252,581 Saint-Sacques Aug. 12, 19412,373,051 Phipps Apr. 3, 1945 2,442,522 Wiegand June 1, 1948

